Not necessarily,
A combination of the two works very well indeed,
On severe black top especially (remember this is, in effect a restoration clean) if you fear the carpet can not take too much moisture, we would spray the worst affected areas with your favourite solution of choice preferably hot, leave to dwell for 10 minutes or so, then using an old pad block, with out a pad, score the surafce of the black top until it has broken up or emulsified, then extract out in the usual manner.
We would then either damp or dry pad to speed drying, repeat the process as necessary, the results are generally very good.
(when you use the block without a pad the black top has to be well lubricated)
You do not need a TM when using this method.